Methods for separation of azeotrope or azeotrope-like compositions of trifluoroiodomethane (cf3i) and trifluoroacetyl chloride (cf3coci)

ABSTRACT

The present disclosure provides azeotrope or azeotrope-like compositions including trifluoroiodomethane (CF 3 I) and trifluoroacetyl chloride (CF 3 COCl), methods of forming same, and methods of separating, or breaking, the azeotrope or azeotrope-like compositions of trifluoroiodomethane (CF 3 I) and trifluoroacetyl chloride (CF 3 COCl).

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No.63/113,577, filed Nov. 13, 2020, which is herein incorporated byreference in its entirety.

FIELD

The present disclosure is related to azeotrope or azeotrope-likecompositions and, in particular, to azeotrope or azeotrope-likecompositions comprising trifluoroiodomethane (CF₃I) and trifluoroacetylchloride (CF₃COCl) and methods of separating, or breaking, suchazeotrope or azeotrope-like compositions.

BACKGROUND

Fluorocarbon based fluids have found widespread use in industry in anumber of applications, including as refrigerants, aerosol propellants,blowing agents, heat transfer media, gaseous dielectrics, and firesuppression.

However, certain compounds such as chlorofluorocarbons (CFCs) andhydrochlorofluorocarbons (HCFCs) are suspected of depleting atmosphericozone and, thus, are harmful to the environment. Moreover, some of thesecompounds are believed to contribute to global warming. Accordingly, itis desirable to use fluorocarbon fluids having low or even zero ozonedepletion potential, such as hydrofluorocarbons (HFCs), or those with aphotolyzable carbon iodine bond, which exhibit short atmosphericlifetime when released at ground level. The use of single componentfluids or azeotrope mixtures, which do not fractionate on boiling andevaporation, is also desirable.

Unfortunately, the identification of new, environmentally-safe,non-fractionating mixtures is complicated due to the fact that azeotropeformation is not predictable.

The industry is continually seeking new fluorocarbon-based mixtures thatoffer alternatives, and are considered environmentally safer substitutesfor CFCs, HCFCs and HFCs in use today. Of particular interest are iodidecontaining compounds and other fluorinated compounds, which have lowozone depletion potentials and low global warming potentials. Suchmixtures are the subject of this disclosure.

Although iodide containing compounds are of great potential interest,the purification of iodide containing compounds such astrifluoroiodomethane (CF₃I) has presented challenges, and techniques forthe removal of impurities from trifluoroiodomethane (CF₃I) such as, forexample, trifluoromethane (HFC-23), are in constant demand. Therefore,separation techniques such as azeotropic distillation, for example,would be highly desirable.

What is needed are compositions and techniques that may be used toprepare iodide containing compounds, such as trifluoroiodomethane(CF₃I), of high purity.

SUMMARY

The present disclosure provides azeotrope or azeotrope-like compositionsof trifluoroiodomethane (CF₃I) and trifluoroacetyl chloride (CF₃COCl).

The present disclosure further provides methods to break the azeotropeor azeotrope-like composition in order to separate the components of theazeotrope or azeotrope-like compositions from one another.

Methods provided by the present disclosure to break the azeotrope orazeotrope-like composition may include extractive distillation,azeotropic extraction, liquid-liquid extraction and absorption. Each ofthese methods may involve the introduction of a solvent.

In one example, the present disclosure provides a method of breaking anazeotrope or azeotrope-like composition comprising trifluoroiodomethane(CF₃I) and trifluoroacetyl chloride (CF₃COCl) by contacting theazeotrope or azeotrope-like composition with a solvent, and extractingone of the trifluoroiodomethane (CF₃I) and the trifluoroacetyl chloride(CF₃COCl) into the solvent to form a first composition including thesolvent and one of the trifluoroiodomethane (CF₃I) and thetrifluoroacetyl chloride (CF₃COCl) and a second composition comprisingthe other of the trifluoroiodomethane (CF₃I) and the trifluoroacetylchloride (CF₃COCl).

The first and second compositions may then be separated from oneanother. Suitable separation methods may include extractivedistillation, for example.

Following separation, the first and second compositions may be furtherpurified, if desired. This further purification may be accomplished byphase separation, distillation, extraction, or chromatographic methods.Following the optional purification step, purified trifluoroiodomethane(CF₃I) may contain trifluoroacetyl chloride (CF₃COCl) in an amount ofabout 1 wt. % or less. Alternatively, purified trifluoroacetyl chloride(CF₃COCl) may contains trifluoroiodomethane (CF₃I) in an amount of about1 wt. % or less.

The present disclosure further provides a method of separating thecomponents of an azeotrope or azeotrope-like composition comprisingtrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I)comprising contacting, within an extractive distillation column, theazeotrope or azeotrope-like composition with a solvent to form a firstcomposition including the solvent and one of the trifluoroiodomethane(CF₃I) and the trifluoroacetyl chloride (CF₃COCl) and a secondcomposition comprising the other of the trifluoroiodomethane (CF₃I) andthe trifluoroacetyl chloride (CF₃COCl). The first and secondcompositions may then be distilled to provide a first distillatecomprising trifluoroacetyl chloride (CF₃COCl) and a first bottomsproduct comprising the solvent and trifluoroiodomethane (CF₃I).Following the distilling step, an additional step of purifying the firstbottoms product by distillation to produce a second distillate and asecond bottoms product may be performed. The second distillate maycomprise purified trifluoroiodomethane (CF₃I) may containtrifluoroacetyl chloride (CF₃COCl) in an amount of about 1 wt. % orless. Alternatively, the second distillate may comprise purifiedtrifluoroacetyl chloride (CF₃COCl) may contain trifluoroiodomethane(CF₃I) in an amount of about 1 wt. % or less.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plot of temperature vs. weight percent trifluoroiodomethane(CF₃I) measured according to Example 1.

FIG. 2 corresponds to Example 3 and is a plot of temperature versuscomposition (mass fraction of trifluoroiodomethane (CF₃I)) with twocurves placed at an arbitrary low-pressure and at an arbitraryhigh-pressure, respectively.

FIG. 3 shows an exemplary pressure swing distillation configuration.

FIG. 4 shows an exemplary extractive distillation configuration.

FIG. 5 shows solubility curves of trifluoroacetyl chloride (CF₃COCl,“TFAC”) and trifluoroiodomethane (CF₃I) in toluene as described inExample 7A.

FIG. 6 shows solubility curves of trifluoroacetyl chloride (CF₃COCl,“TFAC”) and trifluoroiodomethane (CF₃I) in mineral oil as described inExample 8A.

FIG. 7 shows solubility curves of trifluoroacetyl chloride (CF₃COCl,“TFAC”) and trifluoroiodomethane (CF₃I) in acetonitrile as described inExample 9A.

DETAILED DESCRIPTION I. Azeotrope and Azeotrope-Like Compositions

It has been found that trifluoroacetyl chloride (CF₃COCl) formshomogeneous, minimum boiling azeotrope and azeotrope-like compositionsor mixtures with trifluoroiodomethane (CF₃I), and the present disclosureprovides homogeneous azeotrope or azeotrope-like compositions comprisingtrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I). Theazeotrope or azeotrope-like compositions may consist essentially oftrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I), orthe azeotrope or azeotrope-like compositions may consist oftrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I).

The present inventors have found experimentally that trifluoroacetylchloride (CF₃COCl) and trifluoroiodomethane (CF₃I) form an azeotrope orazeotrope-like composition.

An “azeotrope” composition is a unique combination of two or morecomponents. An azeotrope composition can be characterized in variousways. For example, at a given pressure, an azeotrope composition boilsat a constant characteristic temperature which is either greater thanthe higher boiling point component (maximum boiling azeotrope) or lessthan the lower boiling point component (minimum boiling azeotrope). Atthis characteristic temperature the same composition will exist in boththe vapor and liquid phases. The azeotrope composition does notfractionate upon boiling or evaporation. Therefore, the components ofthe azeotrope composition cannot be separated during a phase change.

An azeotrope composition is also characterized in that at thecharacteristic azeotrope temperature, the bubble point pressure of theliquid phase is identical to the dew point pressure of the vapor phase.

The behavior of an azeotrope composition is in contrast with that of anon-azeotrope composition in which during boiling or evaporation, theliquid composition changes to a substantial degree.

For the purposes of the present disclosure, an azeotrope composition ischaracterized as that composition which boils at a constantcharacteristic temperature, the temperature being lower (a minimumboiling azeotrope) than the boiling points of the two or morecomponents, and thereby having the same composition in both the vaporand liquid phases.

One of ordinary skill in the art would understand however that atdifferent pressures, both the composition and the boiling point of theazeotrope composition will vary to some extent. Therefore, depending onthe temperature and/or pressure, an azeotrope composition can have avariable composition. The skilled person would therefore understand thatcomposition ranges, rather than fixed compositions, can be used todefine azeotrope compositions. In addition, an azeotrope may be definedin terms of exact weight percentages of each component of thecompositions characterized by a fixed boiling point at a specifiedpressure.

An “azeotrope-like” composition is a composition of two or morecomponents which behaves substantially as an azeotrope composition.Thus, for the purposes of this disclosure, an azeotrope-like compositionis a combination of two or more different components which, when inliquid form under given pressure, will boil at a substantially constanttemperature, and which will provide a vapor composition substantiallyidentical to the liquid composition undergoing boiling.

For the purposes of this disclosure, an azeotrope-like composition is acomposition or range of compositions which boils at a temperature rangeof between about −46.0° C. and about 90.0° C. at a pressure of betweenabout 4.9 psia and about 348 psia, including, for example, a compositionor range of compositions which boils at a temperature range of about−22.50° C.±0.30° C. at a pressure of about 14.41 psia±0.30 psia.

Azeotrope or azeotrope-like compositions can be identified using anumber of different methods.

For the purposes of this disclosure the azeotrope or azeotrope-likecomposition is identified experimentally using an ebulliometer (Walas,Phase Equilibria in Chemical Engineering, Butterworth-Heinemann, 1985,533-544). An ebulliometer is designed to provide extremely accuratemeasurements of the boiling points of liquids by measuring thetemperature of the vapor-liquid equilibrium.

The boiling points of each of the components alone are measured at aconstant pressure. As the skilled person will appreciate, for a binaryazeotrope or azeotrope-like composition, the boiling point of one of thecomponents of the composition is initially measured. The secondcomponent of the composition is then added in varying amounts and theboiling point of each of the obtained compositions is measured using theebulliometer at said constant pressure.

The measured boiling points are plotted against the composition of thetested composition, for example, for a binary azeotrope, the amount ofthe second component added to the composition, (expressed as eitherweight % or mole %). The presence of an azeotrope composition can beidentified by the observation of a maximum or minimum boilingtemperature which is greater or less than the boiling points of any ofthe components alone.

As the skilled person will appreciate, the identification of theazeotrope or azeotrope-like composition is made by the comparison of thechange in the boiling point of the composition on addition of the secondcomponent to the first component, relative to the boiling point of thefirst component. Thus, it is not necessary that the system be calibratedto the reported boiling point of the particular components in order tomeasure the change in boiling point.

As previously discussed, at the maximum or minimum boiling point, thecomposition of the vapor phase will be identical to the composition ofthe liquid phase. The azeotrope-like composition is therefore thatcomposition of components which provides a substantially constantminimum or maximum boiling point, that is a boiling point between about−46.0° C. and about 90.0° C. at a pressure of between about 4.9 psia andabout 348 psia, such as, for example, a boiling point of about −22.50°C.±0.30° C. at a pressure of about 14.41 psia±0.30 psia, at whichsubstantially constant boiling point the composition of the vapor phasewill be substantially identical to the composition of the liquid phase.

The present disclosure provides an azeotrope or azeotrope-likecomposition which comprises effective amounts of trifluoroacetylchloride (CF₃COCl) and trifluoroiodomethane (CF₃I) to form an azeotropeor azeotrope-like composition. As used herein, the term “effectiveamount” is an amount of each component which, when combined with theother component, results in the formation of an azeotrope orazeotrope-like mixture.

The present azeotrope or azeotrope-like compositions may consistessentially of combinations of trifluoroacetyl chloride (CF₃COCl) andtrifluoroiodomethane (CF₃I) or consist of combinations oftrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I).

As used herein, the term “consisting essentially of”, with respect tothe components of an azeotrope or azeotrope-like composition or mixture,means the composition contains the indicated components in an azeotropeor azeotrope-like ratio, and may contain additional components providedthat the additional components do not form new azeotrope orazeotrope-like systems. For example, azeotrope mixtures consistingessentially of two compounds are those that form binary azeotropes,which optionally may include one or more additional components, providedthat the additional components do not render the mixture non-azeotropicand do not form an azeotrope with either or both of the compounds (e.g.,do not form a ternary or higher azeotrope).

The present disclosure also provides a method of forming an azeotrope orazeotrope-like composition by mixing, combining, or blending, effectiveamounts of, trifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane(CF₃I). Any of a wide variety of methods known in the art for combiningtwo or more components to form a composition can be used in the presentmethods. For example, trifluoroacetyl chloride (CF₃COCl) andtrifluoroiodomethane (CF₃I) can be mixed, blended, or otherwise combinedby hand and/or by machine, as part of a batch or continuous reactionand/or process, or via combinations of two or more such steps. Bothtrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I) arecommercially available and can be procured from several differentvendors. The components can be provided in the required amounts, forexample by weighing and then combining the amounts.

The azeotrope or azeotrope-like composition has a boiling point betweenabout −46.0° C. and about 90.0° C. at a pressure of between about 4.9psia and about 348 psia, and consists essentially of, or consists of,from about 0.5 wt. % to about 99.0 wt. % trifluoroacetyl chloride(CF₃COCl) and from about 1.0 wt. % to about 99.5 wt. %trifluoroiodomethane (CF₃I).

The azeotrope or azeotrope-like composition having a boiling pointbetween about −46.0° C. and about 90.0° C. at a pressure of betweenabout 4.9 psia and about 348 psia may also consist essentially of, orconsist of, about 4.4 wt. %, 10.7 wt. %, 16.9 wt. %, 23.1 wt. %, 29.3wt. %, 35.5 wt. %, 41.9 wt. %, 48.4 wt. %, 55.1 wt. %, 62.1 wt. %, 69.7wt. %, 77.9 wt. %, 87.3 wt. %, or 99.0 wt. % trifluoroacetyl chloride(CF₃COCl), or within any range defined between any two of the foregoingvalues, and about 95.6 wt. %, 89.3 wt. %, 83.1 wt. %, 76.9 wt. %, 70.7wt. %, 64.5 wt. %, 58.1 wt. %, 51.6 wt. %, 44.9 wt. %, 37.9 wt. %, 30.3wt. %, 22.1 wt. %, or 12.7 wt. % trifluoroiodomethane (CF₃I), or withinany range defined between any two of the foregoing values.

Further azeotrope compositions include about 99.5 wt. %trifluoroiodomethane (CF₃I) and about 0.5 wt. % trifluoroacetyl chloride(CF₃COCl) at a temperature of −46.0° C. and a pressure of about 4.9psia; about 95.6 wt. % trifluoroiodomethane (CF₃I) and about 4.4 wt. %trifluoroacetyl chloride (CF₃COCl) at a temperature of −40.0° C. and apressure of about 6.6 psia; about 89.3 wt. % trifluoroiodomethane (CF₃I)and about 10.7 wt. % trifluoroacetyl chloride (CF₃COCl) at a temperatureof −30.0° C. and a pressure of about 10.5 psia; about 83.1 wt. %trifluoroiodomethane (CF₃I) and about 16.9 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of −20.0° C. and a pressure of about16.0 psia; about 76.9 wt. % trifluoroiodomethane (CF₃I) and about 23.1wt. % trifluoroacetyl chloride (CF₃COCl) at a temperature of −10.0° C.and a pressure of about 23.5 psia; about 70.7 wt. % trifluoroiodomethane(CF₃I) and about 29.3 wt. % trifluoroacetyl chloride (CF₃COCl) at atemperature of 0.0° C. and a pressure of about 33.7 psia; about 64.5 wt.% trifluoroiodomethane (CF₃I) and about 35.5 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 10.0° C. and a pressure of about46.9 psia; about 58.1 wt. % trifluoroiodomethane (CF₃I) and about 41.9wt. % trifluoroacetyl chloride (CF₃COCl) at a temperature of 20.0° C.and a pressure of about 63.9 psia; about 51.6 wt. % trifluoroiodomethane(CF₃I) and about 48.4 wt. % trifluoroacetyl chloride (CF₃COCl) at atemperature of 30.0° C. and a pressure of about 85.1 psia; about 44.9wt. % trifluoroiodomethane (CF₃I) and about 55.1 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 40.0° C. and a pressure of about111.4 psia; about 37.9 wt. % trifluoroiodomethane (CF₃I) and about 62.1wt. % trifluoroacetyl chloride (CF₃COCl) at a temperature of 50.0° C.and a pressure of about 143.5 psia; about 30.3 wt. %trifluoroiodomethane (CF₃I) and about 69.7 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 60.0° C. and a pressure of about182.1 psia; about 22.1 wt. % trifluoroiodomethane (CF₃I) and about 77.9wt. % trifluoroacetyl chloride (CF₃COCl) at a temperature of 70.0° C.and a pressure of about 228.2 psia; about 12.7 wt. %trifluoroiodomethane (CF₃I) and about 87.3 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 80.0° C. and a pressure of about283.1 psia; and about 1.0 wt. % trifluoroiodomethane (CF₃I) and about99.0 wt. % trifluoroacetyl chloride (CF₃COCl) at a temperature of 90.0°C. and a pressure of about 348.0 psia.

The azeotrope or azeotrope-like composition may consist essentially of,or consist of, from about 0.5 wt. % to about 25 wt. % trifluoroacetylchloride (CF₃COCl), from about 2 wt. % to about 21 wt. % trifluoroacetylchloride (CF₃COCl), from about 14 wt. % to about 18 wt. %trifluoroacetyl chloride (CF₃COCl) and, in one azeotrope, about 14.87wt. % trifluoroacetyl chloride (CF₃COCl), as well as from about 75 wt. %to about 99.5 wt. % trifluoroiodomethane (CF₃I), from about 79 wt. % toabout 98 wt. % trifluoroiodomethane (CF₃I), from about 82 wt. % to about86 wt. % trifluoroiodomethane (CF₃I) and, in one azeotrope, about 85.13wt. % trifluoroiodomethane (CF₃I). The azeotrope or azeotrope-likecomposition has a boiling point of about −22.50° C.±0.30° C. at apressure of about 14.41 psia±0.30 psia.

In other words, the azeotrope or azeotrope-like composition may consistessentially of, or consist of, from about 0.5 wt. % to about 25 wt. %trifluoroacetyl chloride (CF₃COCl) and from about 75 wt. % to about 99.5wt. % trifluoroiodomethane (CF₃I), or from about 2 wt. % to about 21 wt.% trifluoroacetyl chloride (CF₃COCl) and from about 79 wt. % to about 98wt. % trifluoroiodomethane (CF₃I), or from about 14 wt. % to about 18wt. % trifluoroacetyl chloride (CF₃COCl) and from about 82 wt. % toabout 86 wt. % trifluoroiodomethane (CF₃I) and, in one azeotrope, about14.87 wt. % trifluoroacetyl chloride (CF₃COCl) and about 85.13 wt. %trifluoroiodomethane (CF₃I). The azeotrope or azeotrope-like compositionhas a boiling point of about −22.50° C.±0.30° C. at a pressure of about14.41 psia±0.30 psia.

Stated alternatively, the azeotrope or azeotrope-like compositionconsists essentially of, or consists of, as little as about 0.5 wt. %,about 2 wt. % or about 14 wt. %, or as great as about 18 wt. %, about 21wt. % or about 25 wt. % trifluoroacetyl chloride (CF₃COCl), or withinany range defined between any two of the foregoing values, and theazeotrope or azeotrope-like composition consists essentially of, orconsists of, as little as about 75 wt. %, about 79 wt. % or about 82 wt.%, or as great as about 86 wt. %, about 98 wt. % or about 99.5 wt. %trifluoroiodomethane (CF₃I), or within any range defined between any twoof the foregoing values. The azeotrope composition consists essentiallyof, or consists of, about 14.87 wt. % and trifluoroacetyl chloride(CF₃COCl) and about 85.13 wt. % of trifluoroiodomethane (CF₃I). Theazeotrope or azeotrope-like composition of the present disclosure has aboiling point of about −22.50° C.±0.30° C. at a pressure of about 14.41psia±0.30 psia.

The present disclosure also provides a composition comprising theazeotrope or azeotrope-like composition. For example, there is provideda composition comprising at least about 14 wt. % of the azeotrope orazeotrope-like compositions, or at least about 21 wt. % of the azeotropeor azeotrope-like compositions, or at least about 25 wt. % of theazeotrope or azeotrope-like compositions, or at least about 70 wt. % ofthe azeotrope or azeotrope-like compositions, or at least about 90 wt. %of the azeotrope or azeotrope-like compositions.

II. Separating Impurities from the Azeotrope or Azeotrope-LikeCompositions.

The azeotrope or azeotrope-like composition comprising, consistingessentially of, or consisting of effective amounts of trifluoroacetylchloride (CF₃COCl) and trifluoroiodomethane (CF₃I) disclosed herein maybe used for separating impurities from trifluoroacetyl chloride(CF₃COCl) and/or trifluoroiodomethane (CF₃I). One impurity that may bepresent in trifluoroiodomethane (CF₃I) is trifluoromethane (HFC-23).

The preparation of azeotropic or azeotrope-like compositions comprising,consisting essentially of, or consisting of effective amounts oftrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I)allows separation techniques such as azeotropic distillation, forexample, to be used to remove impurities from trifluoroiodomethane(CF₃I) to provide trifluoroiodomethane (CF₃I) of high purity.

In particular, an azeotrope or azeotrope-like composition comprising,consisting essentially of, or consisting of effective amounts oftrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I) maybe formed from a composition including one or both of trifluoroacetylchloride (CF₃COCl) and trifluoroiodomethane (CF₃I) together with one ormore other chemical compounds other than trifluoroacetyl chloride(CF₃COCl) and trifluoroiodomethane (CF₃I), such as impurities. One suchimpurity is trifluoromethane (HFC-23), for example. Following theformation of the azeotrope or azeotrope-like composition, the azeotropeor azeotrope-like composition may be separated from the other chemicalcompounds by a suitable method, such as by distillation, phaseseparation, or fractionation.

In one example, the present disclosure provides a method of separatingtrifluoroacetyl chloride (CF₃COCl) as an impurity from a primary, crudecomposition of trifluoroiodomethane (CF₃I) which includestrifluoroacetyl chloride (CF₃COCl) as an impurity together with at leastone additional impurity, comprising the steps of providing a primarycomposition of crude trifluoroiodomethane (CF₃I), trifluoroacetylchloride (CF₃COCl) as an impurity, and at least one additional impurity,and subjecting the primary composition to conditions effective to form asecondary composition which is an azeotrope or azeotrope-likecomposition consisting essentially of, or consisting of, effectiveamounts of trifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane(CF₃I), and separating the secondary composition from the primarycomposition by a separation technique such as phase separation,distillation, or fractionation, for example. Thereafter, the secondarycomposition may be subjected to further separation or purification stepsto obtain purified trifluoroiodomethane (CF₃I).

In another example, a composition may be provided which includes one oftrifluoroiodomethane (CF₃I) and trifluoroacetyl chloride (CF₃COCl),together with at least one impurity. To this composition, the other oftrifluoroiodomethane (CF₃I) and trifluoroacetyl chloride (CF₃COCl) isadded in a sufficient amount and the composition is subjected toconditions effective to form a composition which is an azeotrope orazeotrope-like composition consisting essentially of, or consisting of,effective amounts of trifluoroacetyl chloride (CF₃COCl) andtrifluoroiodomethane (CF₃I), followed by separating the azeotrope orazeotrope-like composition from the impurity by a separation techniquesuch as phase separation, distillation, or fractionation, for example.Thereafter, the azeotrope or azeotrope-like composition oftrifluoroiodomethane (CF₃I) and trifluoroacetyl chloride (CF₃COCl) maybe subjected to further separation or purification steps to obtainpurified trifluoroiodomethane (CF₃I).

In another example discussed in detail below in Example 3, the pressuresensitivity of the present azeotropic compositions allows the separationof compositions including trifluoroacetyl chloride (CF₃COCl) andtrifluoroiodomethane (CF₃I) to form essentially pure compositions ofeach of trifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane(CF₃I) by “pressure swing” distillation.

One method of separating trifluoroacetyl chloride (CF₃COCl) andtrifluoroiodomethane (CF₃I) from a primary composition includingtrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I)includes the initial step of conveying a feed stream including theprimary composition to a low-pressure column. A bottoms product may becollected from the low-pressure column which consists essentially ofpure trifluoroacetyl chloride (CF₃COCl). A first distillate is thenconveyed from the low-pressure column to a high-pressure column via apump or compressor to increase the pressure, where the first distillateis an azeotrope or azeotrope-like composition consisting essentially ofeffective amounts of trifluoroacetyl chloride (CF₃COCl) andtrifluoroiodomethane (CF₃I). A second bottoms product may be collectedfrom the high-pressure column which consists essentially of puretrifluoroiodomethane (CF₃I). The method may further include, after thesecond collecting step, the additional step of recycling the seconddistillate from the high-pressure column back to the feed streamcomprising the primary composition.

Similarly, another method of separating trifluoroacetyl chloride(CF₃COCl) and trifluoroiodomethane (CF₃I) from a primary compositionincluding trifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane(CF₃I) includes the initial step of conveying a feed stream includingthe primary composition to a high-pressure column. A bottoms product maybe collected from the high-pressure column which consists essentially ofpure trifluoroiodomethane (CF₃I). A first distillate is then conveyedfrom the high-pressure column to a low-pressure column, where the firstdistillate is an azeotrope or azeotrope-like composition consistingessentially of effective amounts of trifluoroacetyl chloride (CF₃COCl)and trifluoroiodomethane (CF₃I). A second bottoms product may becollected from the low-pressure column which consists essentially oftrifluoroacetyl chloride (CF₃COCl). The method may further include,after the second collecting step, the additional step of recycling asecond distillate from the low-pressure column via a pump or compressorback to the feed stream comprising the primary composition.

III. Breaking the Azeotrope or Azeotrope-Like Compositions.

The components of the azeotrope or azeotrope-like composition(trifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I) maybe difficult to separate from one another; in other words, it may bedifficult to break the azeotrope or azeotrope-like composition.

One method provided by the present disclosure to break the azeotrope orazeotrope-like composition of trifluoroiodomethane (CF₃I) andtrifluoroacetyl chloride (CF₃COCl) comprises contacting the azeotrope orazeotrope-like composition with a solvent, extracting one of thetrifluoroiodomethane (CF₃I) and the trifluoroacetyl chloride (CF₃COCl)into the solvent to form a first composition including the solvent andone of the trifluoroiodomethane (CF₃I) and the trifluoroacetyl chloride(CF₃COCl), and a second composition comprising the other of thetrifluoroiodomethane (CF₃I) and the trifluoroacetyl chloride (CF₃COCl),and separating the first and second compositions. Following separation,the trifluoroiodomethane (CF₃I) and/or the trifluoroacetyl chloride(CF₃COCl) may be purified.

Specifically, the azeotrope or azeotrope-like composition may becontacted with a solvent, to selectively interact with, or absorb, oneof the components of the azeotrope or azeotrope-like composition,resulting in a first composition and a second composition. The firstcomposition comprises a one of the trifluoroiodomethane (CF₃I) and thetrifluoroacetyl chloride (CF₃COCl) and the solvent, depending upon whichof these components of the azeotrope or azeotrope-like mixture thesolvent selectively interacts with. The second composition comprises theother of the trifluoroiodomethane (CF₃I) and the trifluoroacetylchloride (CF₃COCl). The first and second compositions may then beseparated from one another.

As used herein, in connection with breaking the or azeotrope-likecompositions, the term “solvent” refers to one or more chemicalcompounds that selectively interacts with one of the components of theazeotrope or azeotrope-like composition. For example, one of thecomponents of the azeotrope or azeotrope-like composition may beselectively absorbed into the solvent, thereby separating the componentsof the azeotrope or azeotrope-like composition. Suitable solvents mayinclude sulfur dioxide (SO₂), mineral oil, toluene, acetonitrile, or acombination of two or more of these, for example. Mineral oil refers toa light mixture of higher alkanes from a mineral source, such as apetroleum distillate.

In particular, breaking the azeotrope or azeotrope-like compositionoccurs upon contacting the azeotrope or azeotrope-like composition withthe solvent. This may be accomplished by simple blending of azeotrope orazeotrope-like composition with the solvent, such as by mixing or in adistillation column. Optionally, the blend may be subjected todistillation conditions.

After contacting the azeotrope or azeotrope-like composition with thesolvent, sufficient contact time between the azeotrope or azeotrope-likecomposition allows the mixture to reach equilibrium conditions. Onceequilibrium is reached, one component of the azeotrope or azeotrope-likecomposition will be found predominantly in the solvent, while the othercomponent will be predominantly excluded from the solvent.

Specifically, the ratio of trifluoroiodomethane (CF₃I) totrifluoroacetyl chloride (CF₃COCl) in the solvent may be about 2.0:1.0or greater, about 2.5:1.0 or greater, about 3.0:1.0 or greater, about3.5:1.0 or greater, about 5.0:1.0 or greater, about 10.0:1.0 or greater,about 100:1.0 or greater, or about 1000:1.0 or greater. Alternatively,the ratio of trifluoroacetyl chloride (CF₃COCl) to trifluoroiodomethane(CF₃I) in the solvent may be about 2.0:1.0 or greater, about 2.5:1.0 orgreater, about 3.0:1.0 or greater, about 3.5:1.0 or greater 5.0:1.0 orgreater, about 10.0:1.0 or greater, about 100:1.0 or greater, or about1000:1.0 or greater.

Following the addition of the solvent, several possible methods exist bywhich the trifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane(CF₃I) may be separated from one another, including pressure swingdistillation, azeotropic extraction, liquid-liquid extraction,absorption or extractive distillation, for example.

In one example, the present disclosure provides a method to separate thecomponents of the azeotrope or azeotrope-like composition(trifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I)using extractive distillation. As shown in FIG. 4, the azeotrope orazeotrope-like composition 10 may be fed to an extractive distillationcolumn 14. A solvent 12 may be fed to the extractive distillation column14, such that the solvent 12 contacts the azeotrope or azeotrope-likecomposition 10, resulting in a first composition comprising one of thetrifluoroiodomethane (CF₃I) and the trifluoroacetyl chloride (CF₃COCl)which comprises a first distillate 16, and a second compositioncomprising the other of the trifluoroiodomethane (CF₃I) or thetrifluoroacetyl chloride (CF₃COCl) and the solvent, which comprises afirst bottoms product 18. The first distillate 16 may be recycled backto a prior process flow and/or may be subjected to purification. Thefirst bottoms product 18 may then be passed to a distillation column 20to produce a second distillate 22 and a second bottoms product 24. Thesecond distillate 22 comprises a product stream of one of purifiedtrifluoroiodomethane (CF₃I) or purified trifluoroacetyl chloride(CF₃COCl). The second bottoms product 24 comprises recovered solvent,which may be purged 26. Alternatively, the recovered solvent 28 may berecycled, first via an optional cooler 30 to reduce the temperature ofthe solvent. Additional solvent 32 may be added if necessary, and therecovered solvent 28 and additional solvent 32 may be passed to anoptional solvent recovery vessel 34. From the optional solvent recoveryvessel 34, the solvent may pass through a solvent recycle pump 36 tojoin solvent stream 12 prior to being fed to the extractive distillationcolumn 14.

The extractive distillation column may be a single-stage flash column.Alternatively, the extractive distillation column may be a multi-stagecolumn.

In one example of the method shown in FIG. 4, the first composition maycomprise trifluoroacetyl chloride (CF₃COCl) and the second compositionmay comprise trifluoroiodomethane (CF₃I) and the solvent. Followingextractive distillation, the first distillate may comprisetrifluoroacetyl chloride (CF₃COCl), which may be recycled back to thereactor. The first bottoms product, comprising trifluoroiodomethane(CF₃I) and the solvent may then be passed to a distillation column toproduce a second distillate comprising a product stream oftrifluoroiodomethane (CF₃I) and a second bottoms comprising recoveredsolvent, which may be purged or recycled back to the extractivedistillation column. In a further step, the trifluoroiodomethane (CF₃I)may optionally be purified.

The purified trifluoroiodomethane (CF₃I) may contain trifluoroacetylchloride (CF₃COCl) in an amount of about 1 wt. % or less, about 0.8 wt.% or less, 0.7 wt. % or less 0.5 wt. % or less, 0.3 wt. % or less, or0.1 wt. % or less.

In an alternative example of the method shown in FIG. 4, the firstcomposition may comprise trifluoroiodomethane (CF₃I), and the secondcomposition may comprise trifluoroacetyl chloride (CF₃COCl) and thesolvent. Following extractive distillation, the first distillate maycomprise trifluoroiodomethane (CF₃I), which may be recycled back to thereactor. The first bottoms product, comprising trifluoroacetyl chloride(CF₃COCl) and the solvent may then be passed to a distillation column toproduce a second distillate comprising a product stream oftrifluoroacetyl chloride (CF₃COCl) and a second bottoms comprisingrecovered solvent, which may be purged or recycled back to theextractive distillation column. In a further step, the trifluoroacetylchloride (CF₃COCl) may optionally be purified.

The purified trifluoroacetyl chloride (CF₃COCl) may containtrifluoroiodomethane (CF₃I) in an amount of about 1 wt. % or less, about0.8 wt. % or less, 0.7 wt. % or less 0.5 wt. % or less, 0.3 wt. % orless, or 0.1 wt. % or less

The following non-limiting Examples serve to illustrate the disclosure.

EXAMPLES Example 1—Ebulliometer Study

An ebulliometer was used to measure azeotrope and azeotrope-likecompositions of trifluoroacetyl chloride (CF₃COCl) andtrifluoroiodomethane (CF₃I). The ebulliometer included a vacuum jacketedglass vessel which was sealed at the bottom and open to the atmosphereat the top. The top, or condenser jacket, of the ebulliometer was filledwith a mixture of dry ice and ethanol to attain a temperature of about−72° C., which is significantly lower than the saturation temperature of−20.2° C. for trifluoroacetyl chloride (CF₃COCl) and −22.4° C. fortrifluoroiodomethane (CF₃I) at a pressure of 14.4 psia. In this manner,it was ensured that all vapors in the system were condensed and flowedback into the ebulliometer such that the liquid and vapor phases were inequilibrium. A quartz-platinum thermometer with an accuracy of ±0.002°C. was inserted inside the glass vessel and used to determine thetemperature of the condensed vapor corresponding to the equilibriumboiling point of the mixture. Boiling chips were used to assist withmaintaining a smooth boiling of the mixture in the ebulliometer.

The following procedure was used.

1. The quartz thermometer was immersed into a long dewar which containedan ice/water slurry and it was verified that the thermometer read 0° C.The dewar was deep enough so that at least % the length of thethermometer shaft was immersed in the ice/water. The thermometerresistance was recorded in ohms.

2. The condenser jacket was loaded to ¼ full with ethanol. The condenserjacket was cooled by slowly introducing dry ice to avoid boiling overand/or splashing of the ethanol.

3. A known amount of trifluoroiodomethane (CF₃I) or trifluoroacetylchloride (CF₃COCl) was added to the ebulliometer and brought to avigorously refluxing condition. The temperature and atmospheric pressurewere recorded using a barometer with a temperature indicator.

The measurement was carried out in two steps. In a first step, about24.15 g of trifluoroiodomethane (CF₃I) having a purity of 99.88 area %as determined by gas chromatography (GC) was first introduced to theebulliometer by weighing the container before and after the additionusing a balance having an accuracy of ±0.01 g. The liquid was brought toa boil and the equilibrium temperature of the trifluoroiodomethane(CF₃I) was recorded at the recorded barometric pressure. Then,trifluoroacetyl chloride (CF₃COCl) having a purity of 98 area % asdetermined by gas chromatography (GC) was introduced in small incrementsinto the ebulliometer and the equilibrium temperature of the condensedliquid mixture was recorded.

In a second step, about 15.66 g of trifluoroacetyl chloride (CF₃COCl)having a purity of 98 area % as determined by gas chromatography (GC)was introduced to the ebulliometer by weighing the container before andafter the addition using a balance having an accuracy of ±0.01 g. Theliquid was brought to a boil and the equilibrium temperature of thetrifluoroacetyl chloride (CF₃COCl) was recorded at the recordedbarometric pressure. Then, trifluoroiodomethane (CF₃I) having a purityof 99.88 area % as determined by gas chromatography (GC) was introducedin small increments into the ebulliometer and the equilibriumtemperature of the condensed liquid mixture was recorded.

Data from the above first and second steps was combined to complete thecomposition range data from 0 to 100 weight percent of each of thetrifluoroacetyl chloride (CF₃COCl) and the trifluoroiodomethane (CF₃I)presented below in Table 1, which shows a minimum in temperature whichindicates that an azeotrope had been formed, and this data is alsopresented in graphic form in FIG. 1. The bubble point temperature of themixture remained constant indicating that the mixture was azeotrope-likeover a large composition range.

TABLE 1 Ebulliometer Study of CF₃l/Trifluoroacetyl Chloride at P = 14.4psia Temp. Weight % Weight % (° C.) CF₃l CF₃COCl −22.36 100.00 0.00−22.41 97.58 2.42 −22.45 95.80 4.20 −22.50 90.25 9.75 −22.51 85.13 14.87−22.49 82.28 17.72 −22.47 78.66 21.34 −22.44 74.95 25.05 −22.40 70.6829.32 −22.34 65.75 34.25 −22.31 63.84 36.16 −22.21 58.36 41.64 −22.1355.24 44.76 −22.20 58.02 41.98 −22.09 52.73 47.27 −22.03 50.27 49.73−21.89 44.55 55.45 −21.78 39.65 60.35 −21.67 36.80 63.20 −21.58 33.5366.47 −21.23 20.95 79.05 −20.90 15.94 84.06 −20.78 12.47 87.53 −20.689.53 90.47 −20.54 7.17 92.83 −20.45 4.92 95.08 −20.30 2.06 97.94 −20.230.00 100.00

Example 2—Azeotrope Locus

In E. W. Lemmon et al., A Generalized Model for the ThermodynamicProperties of Mixtures, International Journal of Thermophysics, Vol. 20,pp. 825-835 (1999), the authors describe a method for accuratelycharacterizing the thermodynamic properties of mixtures. The proposedHelmholtz Energy Equation of State (HEOS) considers pure component andinteraction parameters of mixture constituents to determine anythermodynamic quantity including mixture vapor and liquid equilibriumcompositions which are used for identifying the existence andcomposition of azeotropes. After reducing the ebulliometer measurementsof Example 1 into the HEOS interaction parameters described on page 828of the foregoing publication, incorporating the pure componentthermodynamic properties of both trifluoroiodomethane (CF₃I) andtrifluoroacetyl chloride (CF₃COCl), and evaluating the vapor-liquidequilibrium compositions using the thermodynamic relationships describedon page 830-831 of the foregoing publication, it was discovered that theazeotropic composition is unusually sensitive to the system temperatureand pressure.

For example, at the system pressure of the ebulliometer in Example 1(14.4 psia), the azeotropic composition was identified at about 85 wt. %CF₃I. However, at an increased system pressure of about 47 psia, theazeotropic composition moves closer to 65 wt. % of trifluoroiodomethane(CF₃I). While not wishing to be bound by theory, the sensitivity of theazeotrope to system conditions appears to be a consequence of therelative volatilities between trifluoroiodomethane (CF₃I) andtrifluoroacetyl chloride (CF₃COCl). Examining the VLE of thesecomponents as a function of different system conditions yields a locusof azeotropes, shown in Table 2.

TABLE 2 Azeotrope Locus Azeotropic Composition Temp. Pressure Wt. % Wt.% (° C.) (psia) CF₃l CF₃COCl −46.0 4.9 99.5 0.5 −40.0 6.6 95.6 4.4 −30.010.5 89.3 10.7 −20.0 16.0 83.1 16.9 −10.0 23.5 76.9 23.1 0.0 33.7 70.729.3 10.0 46.9 64.5 35.5 20.0 63.9 58.1 41.9 30.0 85.1 51.6 48.4 40.0111.4 44.9 55.1 50.0 143.5 37.9 62.1 60.0 182.1 30.3 69.7 70.0 228.222.1 77.9 80.0 283.1 12.7 87.3 90.0 348.0 1.0 99.0

Example 3—Pressure Swing Separation

A well-known consequence of azeotropic mixtures is the inability tofully separate its constituents in a single distillation operation. Forexample, separation of a 50/50 wt. % mixture of trifluoroiodomethane(CF₃I) and trifluoroacetyl chloride (CF₃COCl) by a distillation columnheld at 14.4 psia, exhibiting azeotropic behavior as described byExample 1, would be bounded by compositions between the puretrifluoroacetyl chloride (CF₃COCl) (i.e., 0 wt. % trifluoroiodomethane(CF₃I)) endpoint and the minimum boiling azeotropic composition (about85 wt. % trifluoroiodomethane (CF₃I)). In other words, distillation of amixture at these conditions would be unable to producetrifluoroiodomethane (CF₃I) in a purity greater than 85 wt. %. Toaddress this fundamental barrier of azeotropes and attain both purertrifluoroiodomethane (CF₃I) and trifluoroacetyl chloride (CF₃COCl), adifferent separation strategy must be realized.

As noted by Example 2, the azeotropic composition of binary mixtures oftrifluoroiodomethane (CF₃I) and trifluoroacetyl chloride (CF₃COCl) wasdiscovered to be unusually sensitive to the system conditions. Thissensitivity can be exploited to support better separation throughpressure swing distillation. In this system, a pressure-sensitiveazeotrope is separated using two distillation columns in sequence, oneat an arbitrary, relatively lower pressure and one at an arbitrary,relatively higher pressure. The columns may be disposed such that thelower pressure column is first in the sequence. Alternatively, thehigher pressure column may be first in the sequence. For the purposes ofthis example, with reference to FIGS. 2 and 3, the columns are disposedwith the lower pressure column first in the sequence.

A mixture of trifluoroiodomethane (CF₃I) and trifluoroacetyl chloride(CF₃COCl) is first subjected to distillation at a lower pressure. Theparticular composition of the mixture may be tailored as needed. For thepurposes of this representative example, a mixture comprising 50 wt. %trifluoroiodomethane (CF₃I) and 50 wt. % trifluoroacetyl chloride(CF₃COCl) is used. Referring now to FIG. 2, this mixture is designatedComposition A (“Comp. ‘A’”). Referring now to FIG. 3, the mixture,stream 10, is fed to a distillation column 12 at an arbitrarylow-pressure (20 psia for the purposes of this Example).

As shown in FIG. 2, Composition A (stream 10 in FIG. 3) has not yetreached the azeotrope point. As such, the mixture may be separated intofractions enriched in one component of the mixture and the azeotrope orazeotrope-like composition. Here, fractions enriched in the higherboiling point component, trifluoroacetyl chloride (CF₃COCl), arecollected as the bottoms product and are designated as Composition C(“Comp. ‘C’”) in FIGS. 2 and 3, and stream 16 in FIG. 3. The azeotropeor azeotrope-like composition is designated as Composition B (“Comp.‘B’”) in FIGS. 2 and 3 and is the distillate from the low-pressurecolumn 12 shown in FIG. 3. This mixture is then passed to a column 14 atan arbitrary higher pressure (100 psia for the purposes of thisExample), following stream 14 in FIG. 3.

Referring now to FIG. 2, the point representing Composition B in thehigh-pressure curve is now on the other side of the azeotropiccomposition in comparison to the low-pressure curve. This permitsfractions enriched in the other component of the mixture to becollected. In this Example, fractions enriched in trifluoroiodomethane(CF₃I) are collected as the bottoms product and are designated asComposition D (“Comp. ‘D’”) in FIGS. 2 and 3, and stream 20 in FIG. 3.As with the lower pressure column, the distillate comprises theazeotrope or azeotrope-like mixture. This mixture may be recycled backto co-mingle with Composition A following stream 22 in FIG. 3.

In this way, the barrier of the azeotrope is addressed, using thesensitivity of its composition to the column conditions, to produce twostreams enriched in both components. It is important to note that thedetails in this example are meant to be illustrative. Depending on thecontext of the mixture, the column conditions and configurations can bedesigned to support nearly any desired purities of trifluoroiodomethane(CF₃I) and/or trifluoroacetyl chloride (CF₃COCl).

Example 4—Separation of Impurities

In this Example, a crude composition of trifluoroiodomethane (CF₃I) isprovided, including trifluoroacetyl chloride (CF₃COCl) as an impurity,along with one or more other impurities such as trifluoromethane(HFC-23). The relative amounts of trifluoroiodomethane (CF₃I) andtrifluoroacetyl chloride (CF₃COCl) are altered if necessary to formsufficient relative amounts and the composition is subjected todistillation at conditions effective to form and separate an azeotropeor azeotrope-like composition of trifluoroiodomethane (CF₃I) andtrifluoroacetyl chloride (CF₃COCl) from the remainder of thecomposition. The separated azeotrope or azeotrope-like composition oftrifluoroiodomethane (CF₃I) and trifluoroacetyl chloride (CF₃COCl) isremoved from the remaining crude composition of trifluoroiodomethane(CF₃I) as a light component. The remaining crude composition oftrifluoroiodomethane (CF₃I) is then subjected to different temperatureand pressure conditions wherein the other impurities such astrifluoromethane (HFC-23) may be separated by further distillation toobtain purified trifluoroiodomethane (CF₃I).

Example 5—Separation of Impurities

In this example, a composition is provided which includestrifluoroiodomethane (CF₃I) and at least one impurity such astrifluoromethane (HFC-23), for example. To this composition,trifluoroacetyl chloride (CF₃COCl) is added in a sufficient amount andthe composition is subjected to conditions effective to form acomposition which is an azeotrope or azeotrope-like compositionconsisting essentially of, or consisting of, effective amounts oftrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I),followed by separating the azeotrope or azeotrope-like composition fromthe impurity by a separation technique such as phase separation,distillation, or fractionation, for example. Thereafter, the azeotropeor azeotrope-like composition of trifluoroiodomethane (CF₃I) andtrifluoroacetyl chloride (CF₃COCl) may be subjected to furtherseparation or purification steps to obtain purified trifluoroiodomethane(CF₃I).

Example 6—Separation of Impurities

In this example, a composition is provided which includestrifluoroacetyl chloride (CF₃COCl) and at least one impurity such astrifluoromethane (HFC-23), for example. To this composition,trifluoroiodomethane (CF₃I) is added in a sufficient amount and thecomposition is subjected to conditions effective to form a compositionwhich is an azeotrope or azeotrope-like composition consistingessentially of, or consisting of, effective amounts of trifluoroacetylchloride (CF₃COCl) and trifluoroiodomethane (CF₃I), followed byseparating the azeotrope or azeotrope-like composition from the impurityby a separation technique such as phase separation, distillation, orfractionation, for example. Thereafter, the azeotrope or azeotrope-likecomposition of trifluoroiodomethane (CF₃I) and trifluoroacetyl chloride(CF₃COCl) may be subjected to further separation or purification stepsto obtain purified trifluoroiodomethane (CF₃I).

Example 7A—Differential Solubility of Trifluoroiodomethane (CF₃I) andTrifluoroacetyl Chloride (CF₃COCl) in Toluene

Static Vapor-Liquid Equilibrium Methods are a class of experimentaltechniques that can be used to identify thermodynamic interactionsbetween a solvent (i.e. absorbing species) and a target solute (i.e.species being absorbed). One such technique, known as the PTx method,collects measurements of the total saturation pressure (“P”) exerted bymixtures of known compositions (“x”) at fixed temperatures (“T”) andcell volumes. (Walas, Phase Equilibria in Chemical Engineering,Butterworth-Heinemann, 1985, pp. 537). Using data collected from the PTxexperiment, as well as pure component properties of constituents of themixtures, the thermodynamic properties of the mixtures can be accuratelycharacterized by fitting the component's interaction parameters in awell-defined thermodynamic equation; one such equation is the Nonrandom,Two-liquid (NRTL) activity coefficient model by Renon and Prausnitz(Local Compositions in Thermodynamic Excess Functions for LiquidMixtures, AIChE Journal, Vol. 14, January 1968, pp. 135-144).

From a well-characterized thermodynamic model (such as NRTL fit againstPTx data), solubility curves can be generated. The solubility is definedas the liquid composition of the solute in the liquid phase atsaturation, generally as a function of pressure and temperature. Bycomparing solubility curves for different solutes, the solvent'sselectivity (i.e. preference) towards a particular solute can beidentified; the larger the selectivity the more the solvent prefers toabsorb one species while rejecting the other.

A set of volume calibrated PTx cells were used to measure the solubilitycharacteristics of trifluoroiodomethane (CF₃I) in toluene as well astrifluoroacetyl chloride (CF₃COCl) in toluene. Mixtures oftrifluoroiodomethane (CF₃I) and toluene as well as trifluoroacetylchloride (CF₃COCl) and toluene were gravimetrically prepared intoevacuated PTx cells. Once prepared, each of up to four cells ofdiffering compositions were inserted into a thermostated chamber. In thechamber, each cell was attached to an instrumentation manifold equippedwith calibrated pressure transducers and resistance temperaturedetectors (RTD); this provided a means to measure and record the totalsaturation pressure of each cell's contents at its local temperature. Toestablish equilibrium at a target temperature, the set point of thechamber was adjusted sequentially to −10° C., 10° C., 30° C., or 50° C.Once at equilibrium, recognized when temperature and pressures of eachcell remain stable for several hours, the local temperature andsaturation pressures of each cell were recorded and adjustments for thenext set point were made. From these pressure-temperature-compositiondata, the binary interaction parameters of trifluoroiodomethane (CF₃I)with toluene and trifluoroacetyl chloride (CF₃COCl) with toluene for theNRTL activity coefficient model were identified. These data and modelfit for both trifluoroiodomethane (CF₃I) with toluene andtrifluoroacetyl chloride (CF₃COCl) with toluene are reported in Table 3and Table 4 respectively.

Table 3, below, shows the PTx data for trifluoroiodomethane (CF₃I) withtoluene fit against the NRTL activity coefficient model. The measuredsaturation pressure (P) is compared to the model's saturated pressure(PNRTL) with corresponding absolute deviations (|Δ|).

TABLE 3 Composition Data Model (NRTL) (mass %) T P P_(NRTL) |Δ| TolueneCF₃l (° C.) (psia) (psia) (psia) 94.1%  5.9% −9.81 0.7 0.6 0.1 88.5%11.5% −9.86 1.0 1.2 0.2 79.6% 20.4% −9.70 2.3 2.2 0.1 58.4% 41.6% −9.525.3 5.2 0.2 94.1%  5.9% 9.78 1.5 1.5 0.1 88.5% 11.5% 9.76 2.5 2.7 0.279.6% 20.4% 10.27 5.0 4.8 0.2 58.4% 41.6% 10.12 10.7 10.7 0.0 94.1% 5.9% 29.38 3.0 2.9 0.1 88.5% 11.5% 29.53 4.7 5.1 0.4 79.6% 20.4% 29.839.1 8.9 0.2 58.4% 41.6% 29.83 19.2 19.3 0.1 94.1%  5.9% 49.35 5.5 5.30.2 88.5% 11.5% 49.46 8.5 8.8 0.3 79.6% 20.4% 49.82 15.2 15.0 0.2 58.4%41.6% 49.78 31.6 31.5 0.1

Table 4, below, shows the PTx data for trifluoroacetyl chloride(CF₃COCl) with toluene fit against the NRTL activity coefficient model.The measured saturation pressure (P) is compared to the model'ssaturated pressure (PNRTL) with corresponding absolute deviations (|Δ|).

TABLE 4 Composition Data Model (NRTL) (mass %) T P P_(NRTL) |Δ| TolueneCF₃COCl (° C.) (psia) (psia) (psia) 94.1%  5.9% −9.59 3.3 3.3 0.0 88.1%11.9% −9.62 6.1 6.0 0.1 79.2% 20.8% −9.54 9.3 9.1 0.2 58.7% 41.3% −9.6613.5 13.5 0.0 94.1%  5.9% 9.90 5.8 5.9 0.0 88.1% 11.9% 10.02 11.0 10.80.2 79.2% 20.8% 10.05 16.9 16.7 0.2 58.7% 41.3% 10.07 26.0 25.9 0.094.1%  5.9% 29.40 9.5 9.6 0.1 88.1% 11.9% 29.55 17.6 17.6 0.1 79.2%20.8% 29.63 27.6 27.6 0.0 58.7% 41.3% 29.71 44.3 44.5 0.2 94.1%  5.9%49.23 14.2 14.6 0.3 88.1% 11.9% 49.49 26.2 26.4 0.3 79.2% 20.8% 49.5041.4 41.8 0.5 58.7% 41.3% 49.63 69.2 70.0 0.8

Using the NRTL model generated from the PTx data, the solubility of bothtrifluoroiodomethane (CF₃I) and trifluoroacetyl chloride (CF₃COCl) for agiven temperature and pressure can be determined and compared. As shownin FIG. 5, trifluoroiodomethane (CF₃I) solubility is about 40.8 mass %while trifluoroacetyl chloride (CF₃COCl) solubility is about 11.6 mass %around ambient conditions. This demonstrates that toluene is about 3.5times more selective towards trifluoroiodomethane (CF₃I) overtrifluoroacetyl chloride (CF₃COCl) under these conditions, and generallymore selective towards trifluoroiodomethane (CF₃I) under otherconditions.

Example 7B—Extractive Distillation of Trifluoroiodomethane (CF₃I) inToluene

A gas-phase stream comprising an azeotrope or azeotrope-like compositioncomprising trifluoroiodomethane (CF₃I) in an amount of 75 wt. % andtrifluoroacetyl chloride (CF₃COCl) in an amount of 25 wt. % is routed tothe bottom of an extractive distillation column. However, the foregoingcomposition is exemplary and the technique embodied in this Example maybe used to separate any composition of trifluoroiodomethane (CF₃I) andtrifluoroacetyl chloride (CF₃COCl). A liquid-phase solvent streamcomprising toluene in an amount of 99.99 wt. % and trifluoroiodomethanein an amount of 0.01 wt. % is routed to the top of the extractivedistillation column. The gas-phase stream is bubbled through theliquid-phase stream within the extractive distillation column toselectively absorb the trifluoroiodomethane (CF₃I) into the toluene.

The extractive distillation results in a first distillate streamcomprising trifluoroiodomethane (CF₃I) in an amount of 66.50 wt. %,trifluoroacetyl chloride (CF₃COCl) in an amount of 33.31 wt. %, andtoluene in an amount of 0.19 wt. %. This distillate stream may berecycled back to the reactors described in the above Examples. Theextractive distillation further results in a first bottoms productstream comprising trifluoroiodomethane (CF₃I) in an amount of 20.03 wt.%, toluene in an amount of 79.95 wt. %, and trifluoroacetyl chloride(CF₃COCl) in an amount of 0.01%. The bottoms stream may then be routedto a solvent recovery distillation column. The distillation results in asecond distillate stream comprising purified trifluoroiodomethane (CF₃I)in an amount of 99.94 wt. % and trifluoroacetyl chloride (CF₃COCl) in anamount of 0.06 wt. %. The distillation further results in a secondbottoms product stream comprising toluene in an amount of 99.99 wt. %and trifluoroiodomethane (CF₃I) in an amount of 0.01 wt. %. The secondbottoms product may be recycled through a solvent phase cooler to passback to the extractive distillation column.

Example 8A—Differential Solubility of Trifluoroiodomethane (CF₃I) andTrifluoroacetyl Chloride (CF₃COCl) in Mineral Oil

Following the same procedure described in Example 7A, the PTx behaviorof trifluoroiodomethane (CF₃I) with mineral oil and trifluoroacetylchloride (CF₃COCl) with mineral oil was studied at temperatures of 0°C., 20° C., 40° C., and 60° C. Unlike toluene (a single aromatichydrocarbon entity), the mineral oil solvent comprised a mixture severaltypes of hydrocarbons such as alkanes, cycloalkanes, and others. Fromthe pressure-temperature-composition data, the binary interactionparameters of trifluoroiodomethane (CF₃I) with mineral oil andtrifluoroacetyl chloride (CF₃COCl) with mineral oil for the NRTLactivity coefficient model were identified. The data and model fit arereported in Table 5 and Table 6 respectively.

Table 5, below, shows PTx data for trifluoroiodomethane (CF₃I) withmineral oil fit against the NRTL activity coefficient model. Themeasured saturation pressure (P) is compared to the model's saturatedpressure (PNRTL) with corresponding absolute deviations (|Δ|).

TABLE 5 Composition (mass %) Data Model (NRTL) Mineral T P P_(NRTL) |Δ|Oil CF₃l (° C.) (psia) (psia) (psia) 94.3%  5.7% 0.02 4.9 4.3 0.6 90.7% 9.3% 0.02 5.9 6.6 0.7 78.7% 21.3% 0.22 12.6 13.0 0.4 59.9% 40.1% 0.2721.1 20.1 1.0 94.3%  5.7% 19.74 7.3 7.0 0.3 90.7%  9.3% 19.86 9.7 10.91.2 78.7% 21.3% 20.13 21.9 22.6 0.7 59.9% 40.1% 20.03 37.5 36.1 1.494.3%  5.7% 39.62 10.5 9.7 0.8 90.7%  9.3% 39.67 14.9 15.4 0.5 78.7%21.3% 39.98 34.1 33.9 0.2 59.9% 40.1% 39.95 60.6 57.7 2.9 94.3%  5.7%59.19 12.4 12.2 0.2 90.7%  9.3% 59.37 18.9 19.6 0.7 78.7% 21.3% 59.8044.9 45.7 0.8 59.9% 40.1% 59.72 83.5 83.0 0.5

Table 6, below, shows PTx data for trifluoroacetyl chloride (CF₃COCl)with mineral oil fit against the NRTL activity coefficient model. Themeasured saturation pressure (P) is compared to the model's saturatedpressure (PNRTL) with corresponding absolute deviations (|Δ|).

TABLE 6 Composition (mass %) Data Model (NRTL) Mineral T P P_(NRTL) |Δ|Oil CF₃COCl (° C.) (psia) (psia) (psia) 94.8%  5.2% 0.24 13.2 12.3 0.989.3% 10.7% 0.19 19.4 20.7 1.3 78.8% 21.2% 0.30 28.8 28.6 0.2 59.2%40.8% 0.21 31.7 31.2 0.5 94.8%  5.2% 19.83 17.7 18.3 0.6 89.3% 10.7%19.90 31.9 33.1 1.2 78.8% 21.2% 19.89 50.0 50.4 0.4 59.2% 40.8% 19.9460.9 59.8 1.1 94.8%  5.2% 39.51 25.6 24.6 1.0 89.3% 10.7% 39.66 47.547.2 0.3 78.8% 21.2% 39.71 79.1 79.0 0.1 59.2% 40.8% 39.83 103.5 103.80.3 94.8%  5.2% 59.09 30.4 30.7 0.3 89.3% 10.7% 59.28 60.8 61.4 0.678.8% 21.2% 59.30 112.2 110.7 1.5 59.2% 40.8% 59.50 162.5 162.6 0.1

Using the NRTL model generated from the PTx data, the solubility of bothtrifluoroiodomethane (CF₃I) and trifluoroacetyl chloride (CF₃COCl) for agiven temperature and pressure can be determined and compared. As shownin FIG. 6, trifluoroiodomethane (CF₃I) solubility is about 12.2 mass %while trifluoroacetyl chloride (CF₃COCl) solubility is about 3.6 mass %at or near ambient conditions. This demonstrates that mineral oil isabout 3.4 times more selective towards trifluoroiodomethane (CF₃I) overtrifluoroacetyl chloride (CF₃COCl) under these conditions, and generallymore selective towards trifluoroiodomethane (CF₃I) under otherconditions.

Example 8B—Extractive Distillation of Trifluoroiodomethane (CF₃I) inMineral Oil

As described in Example 7B, a gas-phase stream comprising an azeotropeor azeotrope-like composition comprising trifluoroiodomethane (CF₃I) andtrifluoroacetyl chloride (CF₃COCl) is routed to the bottom of anextractive distillation column. A liquid-phase solvent stream comprisingmineral oil and trifluoroiodomethane is routed to the top of theextractive distillation column. The gas-phase stream is bubbled throughthe liquid-phase stream within the extractive distillation column toselectively absorb the trifluoroiodomethane (CF₃I) into the mineral oil.

The extractive distillation results in a first distillate streamcomprising trifluoroiodomethane (CF₃I) in an amount greater than theamount of trifluoroacetyl chloride (CF₃COCl), as well as a small amountof mineral oil. This distillate stream may be recycled back to thereactors described in the above Examples. The extractive distillationfurther results in a first bottoms product stream comprisingtrifluoroiodomethane (CF₃I), mineral oil, and a small amount of residualtrifluoroacetyl chloride (CF₃COCl). The first bottoms product stream maythen be routed to a solvent recovery distillation column. Thedistillation results in a second distillate stream comprising purifiedtrifluoroiodomethane (CF₃I) and a small amount of residualtrifluoroacetyl chloride (CF₃COCl). The distillation further results ina second bottoms product stream comprising mineral oil and a smallamount of residual trifluoroiodomethane (CF₃I). The second bottomsproduct may be recycled through a solvent phase cooler to pass back tothe extractive distillation column.

Example 9A—Differential Solubility of Trifluoroiodomethane (CF₃I) andTrifluoroacetyl Chloride (CF₃COCl) in Acetonitrile

Following the same procedure as described in Example 7A, the PTxbehavior of trifluoroiodomethane (CF₃I) with acetonitrile andtrifluoroacetyl chloride (CF₃COCl) with acetonitrile was studied attemperatures of −10° C., 10° C., 30° C., and 50° C. From thepressure-temperature-composition data, the binary interaction parametersof trifluoroiodomethane (CF₃I) with acetonitrile and trifluoroacetylchloride (CF₃COCl) with acetonitrile for the NRTL activity coefficientmodel were identified. The data and model fit are reported in Table 7and Table 8 respectively.

Table 7, below, shows PTx data for trifluoroiodomethane (CF₃I) withacetonitrile fit against the NRTL activity coefficient model. Themeasured saturation pressure (P) is compared to the model's saturatedpressure (PNRTL) with corresponding absolute deviations (|Δ|).

TABLE 7 Composition Data Model (NRTL) (mass %) T P P_(NRTL) |Δ|Acetonitrile CF₃l (° C.) (psia) (psia) (psia) 93.9%  6.1% −9.61 0.9 0.90.0 88.5% 11.5% −9.76 1.3 1.4 0.1 79.5% 20.5% −9.65 2.6 2.4 0.2 57.9%42.1% −9.49 5.3 5.4 0.1 93.9%  6.1% 9.99 2.2 2.1 0.1 88.5% 11.5% 9.753.2 3.3 0.1 79.5% 20.5% 10.17 5.7 5.4 0.3 57.9% 42.1% 10.08 11.0 11.30.3 93.9%  6.1% 29.47 4.4 4.4 0.0 88.5% 11.5% 29.55 6.4 6.6 0.2 79.5%20.5% 29.92 10.7 10.5 0.2 57.9% 42.1% 29.93 20.4 20.7 0.3 93.9%  6.1%49.38 8.5 8.6 0.1 88.5% 11.5% 49.51 11.7 12.1 0.4 79.5% 20.5% 49.86 18.418.1 0.3 57.9% 42.1% 49.78 34.3 33.7 0.6

Table 8, below, shows PTx data for trifluoroacetyl chloride (CF₃COCl)with acetonitrile fit against the NRTL activity coefficient model. Themeasured saturation pressure (P) is compared to the model's saturatedpressure (PNRTL) with corresponding absolute deviations (|Δ|).

TABLE 8 Composition Data Model (NRTL) (mass %) T P P_(NRTL) |Δ|Acetonitrile CF₃COCl (° C.) (psia) (psia) (psia) 94.7%  5.3% −9.27 1.92.1 0.2 88.1% 11.9% −9.41 4.6 4.3 0.3 78.6% 21.4% −9.56 7.9 7.4 0.559.7% 40.3% −9.60 12.3 12.8 0.5 94.7%  5.3% 9.88 4.0 4.1 0.1 88.1% 11.9%10.01 8.4 8.2 0.2 78.6% 21.4% 10.03 14.3 13.9 0.4 59.7% 40.3% 10.11 24.224.5 0.3 94.7%  5.3% 29.55 7.2 7.4 0.2 88.1% 11.9% 29.67 14.4 14.1 0.378.6% 21.4% 29.69 24.0 23.7 0.3 59.7% 40.3% 29.76 42.0 42.1 0.1 94.7% 5.3% 49.32 12.5 12.7 0.2 88.1% 11.9% 49.48 23.0 22.8 0.2 78.6% 21.4%49.53 37.4 37.4 0.0 59.7% 40.3% 49.65 66.4 66.6 0.2

Using the NRTL model generated from the PTx data, the solubility of bothtrifluoroiodomethane (CF₃I) and trifluoroacetyl chloride (CF₃COCl) for agiven temperature and pressure can be determined and compared. As shownin FIG. 7, trifluoroiodomethane (CF₃I) solubility is about 39.0 mass %while trifluoroacetyl chloride (CF₃COCl) solubility is about 15.8 mass %at or near ambient conditions. This demonstrates that acetonitrile isabout 2.5 times more selective towards trifluoroiodomethane (CF₃I) overtrifluoroacetyl chloride (CF₃COCl) under these conditions, and generallymore selective towards trifluoroiodomethane (CF₃I) under otherconditions.

Example 9B—Extractive Distillation of Trifluoroiodomethane (CF₃I) inAcetonitrile

As described in Example 7B, a gas-phase stream comprising an azeotropeor azeotrope-like composition comprising trifluoroiodomethane (CF₃I) andtrifluoroacetyl chloride (CF₃COCl) is routed to the bottom of anextractive distillation column. A liquid-phase solvent stream comprisingacetonitrile and trifluoroiodomethane is routed to the top of theextractive distillation column. The gas-phase stream is bubbled throughthe liquid-phase stream within the extractive distillation column toselectively absorb the trifluoroiodomethane (CF₃I) into theacetonitrile.

The extractive distillation results in a first distillate streamcomprising trifluoroiodomethane (CF₃I) in an amount greater than theamount of trifluoroacetyl chloride (CF₃COCl), as well as a small amountof acetonitrile. This distillate stream may be recycled back to thereactors described in the above Examples. The extractive distillationfurther results in a first bottoms product stream comprisingtrifluoroiodomethane (CF₃I), acetonitrile, and a small amount ofresidual trifluoroacetyl chloride (CF₃COCl). The first bottoms productstream may then be routed to a solvent recovery distillation column. Thedistillation results in a second distillate stream comprising purifiedtrifluoroiodomethane (CF₃I) and a small amount of residualtrifluoroacetyl chloride (CF₃COCl). The distillation further results ina second bottoms product stream comprising acetonitrile and a smallamount of residual trifluoroiodomethane (CF₃I). The second bottomsproduct may be recycled through a solvent phase cooler to pass back tothe extractive distillation column.

Aspects

Aspect 1 is an azeotrope or azeotrope-like composition comprising,consisting essentially of, or consisting of effective amounts oftrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I).

Aspect 2 is the azeotrope or azeotrope-like composition of Aspect 1,wherein the azeotrope or azeotrope-like composition has a boiling pointbetween about −46.0° C. and about 90.0° C. at a pressure of betweenabout 4.9 psia and about 348 psia.

Aspect 3 is the azeotrope or azeotrope-like composition of Aspects 1 or2, wherein the azeotrope or azeotrope-like composition consistsessentially of from about 0.5 wt. % to about 99.0 wt. % trifluoroacetylchloride (CF₃COCl) and from about 1.0 wt. % to about 99.5 wt. %trifluoroiodomethane (CF₃I).

Aspect 4 is an azeotrope composition including about 99.5 wt. %trifluoroiodomethane (CF₃I) and about 0.5 wt. % trifluoroacetyl chloride(CF₃COCl) at a temperature of −46.0° C. and a pressure of about 4.9psia.

Aspect 5 is an azeotrope composition including about 95.6 wt. %trifluoroiodomethane (CF₃I) and about 4.4 wt. % trifluoroacetyl chloride(CF₃COCl) at a temperature of −40.0° C. and a pressure of about 6.6psia.

Aspect 6 is an azeotrope composition including about 89.3 wt. %trifluoroiodomethane (CF₃I) and about 10.7 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of −30.0° C. and a pressure of about10.5 psia.

Aspect 7 is an azeotrope composition including about 83.1 wt. %trifluoroiodomethane (CF₃I) and about 16.9 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of −20.0° C. and a pressure of about16.0 psia.

Aspect 8 is an azeotrope composition including about 76.9 wt. %trifluoroiodomethane (CF₃I) and about 23.1 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of −10.0° C. and a pressure of about23.5 psia.

Aspect 9 is an azeotrope composition including about 70.7 wt. %trifluoroiodomethane (CF₃I) and about 29.3 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 0.0° C. and a pressure of about33.7 psia.

Aspect 10 is an azeotrope composition including about 64.5 wt. %trifluoroiodomethane (CF₃I) and about 35.5 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 10.0° C. and a pressure of about46.9 psia.

Aspect 11 is an azeotrope composition including about 58.1 wt. %trifluoroiodomethane (CF₃I) and about 41.9 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 20.0° C. and a pressure of about63.9 psia.

Aspect 12 is an azeotrope composition including about 51.6 wt. %trifluoroiodomethane (CF₃I) and about 48.4 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 30.0° C. and a pressure of about85.1 psia.

Aspect 13 is an azeotrope composition including about 44.9 wt. %trifluoroiodomethane (CF₃I) and about 55.1 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 40.0° C. and a pressure of about111.4 psia.

Aspect 14 is an azeotrope composition including about 37.9 wt. %trifluoroiodomethane (CF₃I) and about 62.1 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 50.0° C. and a pressure of about143.5 psia.

Aspect 15 is an azeotrope composition including about 30.3 wt. %trifluoroiodomethane (CF₃I) and about 69.7 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 60.0° C. and a pressure of about182.1 psia.

Aspect 16 is an azeotrope composition including about 22.1 wt. %trifluoroiodomethane (CF₃I) and about 77.9 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 70.0° C. and a pressure of about228.2 psia.

Aspect 17 is an azeotrope composition including about 12.7 wt. %trifluoroiodomethane (CF₃I) and about 87.3 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 80.0° C. and a pressure of about283.1 psia.

Aspect 18 is an azeotrope composition including about 1.0 wt. %trifluoroiodomethane (CF₃I) and about 99.0 wt. % trifluoroacetylchloride (CF₃COCl) at a temperature of 90.0° C. and a pressure of about348.0 psia.

Aspect 19 is the azeotrope or azeotrope-like composition of Aspect 1,comprising, consisting essentially of, or consisting of from about 0.5wt. % to about 25 wt. % trifluoroacetyl chloride (CF₃COCl) and fromabout 75 wt. % to about 99.5 wt. % trifluoroiodomethane (CF₃I).

Aspect 20 is the azeotrope or azeotrope-like composition of Aspect 19,comprising, consisting essentially of, or consisting of from about 2 wt.% to about 21 wt. % trifluoroacetyl chloride (CF₃COCl) and from about 79wt. % to about 98 wt. % trifluoroiodomethane (CF₃I).

Aspect 21 is the azeotrope or azeotrope-like composition of Aspect 20,comprising, consisting essentially of, or consisting of from about 14wt. % to about 18 wt. % trifluoroacetyl chloride (CF₃COCl) and fromabout 82 wt. % to about 86 wt. % trifluoroiodomethane (CF₃I).

Aspect 22 is the azeotrope or azeotrope-like composition of Aspect 21,comprising, consisting essentially of, or consisting of about 14.87 wt.% trifluoroacetyl chloride (CF₃COCl) and about 85.13 wt. %trifluoroiodomethane (CF₃I).

Aspect 23 is the azeotrope or azeotrope-like composition of any ofAspects 19 to 22, wherein the composition has a boiling point of about−22.50° C.±0.30° C. at a pressure of about 14.41 psia±0.30 psia.

Aspect 24 is the azeotrope or azeotrope-like composition of any ofAspects 1 to 18, consisting essentially of trifluoroacetyl chloride(CF₃COCl) and trifluoroiodomethane (CF₃I).

Aspect 25 is the azeotrope or azeotrope-like composition of any ofAspects 1 to 18, consisting of trifluoroacetyl chloride (CF₃COCl) andtrifluoroiodomethane (CF₃I).

Aspect 26 is a composition comprising, consisting essentially of, orconsisting of the azeotrope or azeotrope-like composition of any ofAspects 1 to 18.

Aspect 27 is the composition of Aspect 26, comprising, consistingessentially of, or consisting of at least about 5 wt. % of the azeotropeor azeotrope-like composition.

Aspect 28 is the composition of Aspect 27, comprising, consistingessentially of, or consisting of at least about 15 wt. % of theazeotrope or azeotrope-like composition.

Aspect 29 is the composition of Aspect 28, comprising, consistingessentially of, or consisting of at least about 50 wt. % of theazeotrope or azeotrope-like composition.

Aspect 30 is the composition of Aspect 29, comprising, consistingessentially of, or consisting of at least about 70 wt. % of theazeotrope or azeotrope-like composition.

Aspect 31 is the composition of Aspect 30, comprising, consistingessentially of, or consisting of at least about 90 wt. % of theazeotrope or azeotrope-like composition.

Aspect 32 is a method of forming an azeotrope or azeotrope-likecomposition comprising the step of combining trifluoroacetyl chloride(CF₃COCl) and trifluoroiodomethane (CF₃I) to form an azeotrope orazeotrope-like composition comprising, consisting essentially of, orconsisting of trifluoroacetyl chloride (CF₃COCl) andtrifluoroiodomethane (CF₃I) having a boiling point between about −46.0°C. and about 90.0° C. at a pressure of between about 4.9 psia and about348 psia.

Aspect 33 is the method of Aspect 32, wherein the combining stepcomprises combining from about 0.5 wt. % to about 99.0 wt. %trifluoroacetyl chloride (CF₃COCl) and from about 1.0 wt. % to about99.5 wt. % trifluoroiodomethane (CF₃I).

Aspect 34 is a method of forming an azeotrope or azeotrope-likecomposition comprising the step of combining trifluoroacetyl chloride(CF₃COCl) and trifluoroiodomethane (CF₃I) to form the azeotrope orazeotrope-like composition comprising effective amounts oftrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I).

Aspect 35 is the method of Aspect 34, the method comprising the step ofcombining trifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane(CF₃I) to form the azeotrope or azeotrope-like composition of any ofAspects 1 to 18.

Aspect 35 is a method of separating trifluoroacetyl chloride (CF₃COCl)and trifluoroiodomethane (CF₃I) from a primary composition comprisingtrifluoroacetyl chloride (CF₃COCl), trifluoroiodomethane (CF₃I) and atleast one impurity, comprising the steps of forming, within the primarycomposition, a secondary composition which is an azeotrope orazeotrope-like composition comprising, consisting essentially of, orconsisting of effective amounts of trifluoroacetyl chloride (CF₃COCl)and trifluoroiodomethane (CF₃I) having a boiling point between about−46.0° C. and about 9-0.0° C. at a pressure of between about 4.9 psiaand about 348 psia; and separating the secondary composition from theprimary composition and the at least one impurity.

Aspect 36 is the method of Aspect 35, wherein the forming step comprisesforming, within the primary composition, a secondary composition whichis an azeotrope or azeotrope-like composition comprising, consistingessentially of, or consisting of from about 0.5 wt. % to about 99.0 wt.% trifluoroacetyl chloride (CF₃COCl) and from about 1.0 wt. % to about99.5 wt. % trifluoroiodomethane (CF₃I).

Aspect 37 is the method of Aspect 35 or Aspect 36, wherein the azeotropeor azeotrope-like composition is as defined in any of Aspects 1 to 18.

Aspect 38 is the method of Aspect 35 or Aspect 36, in which theseparation is carried out by at least one of phase separation,distillation, and fractionation.

Aspect 39 is a method of separating trifluoroacetyl chloride (CF₃COCl)and trifluoroiodomethane (CF₃I) from a primary composition comprisingtrifluoroacetyl chloride (CF₃COCl), trifluoroiodomethane (CF₃I) and atleast one impurity, comprising the steps of forming, within the primarycomposition, a secondary composition which is an azeotrope orazeotrope-like composition comprising, consisting essentially of, orconsisting of effective amounts of trifluoroacetyl chloride (CF₃COCl)and trifluoroiodomethane (CF₃I); and separating the secondary azeotropeor azeotrope-like composition from the primary composition and the atleast one impurity.

Aspect 40 is the method of Aspect 39, wherein the azeotrope orazeotrope-like composition is as defined in any of Aspects 1 to 18.

Aspect 41 is the method of Aspect 39 or Aspect 40, in which theseparation is carried out by at least one of phase separation,distillation, and fractionation.

Aspect 42 is a method of separating trifluoroacetyl chloride (CF₃COCl)or trifluoroiodomethane (CF₃I) from at least one impurity, comprisingthe steps of providing a composition which includes one oftrifluoroiodomethane (CF₃I) and trifluoroacetyl chloride (CF₃COCl),together with at least one impurity; adding a sufficient amount of theother of trifluoroiodomethane (CF₃I) and trifluoroacetyl chloride(CF₃COCl) and subjecting the composition to conditions effective to forma composition which is an azeotrope or azeotrope-like compositionconsisting essentially of, or consisting of, effective amounts oftrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I), andseparating the azeotrope or azeotrope-like composition from theimpurity.

Aspect 43 is the method of Aspect 42, wherein the azeotrope orazeotrope-like composition is as defined in any of Aspects 1 to 18.

Aspect 44 is the method of Aspect 42 or Aspect 43, in which theseparation is carried out by at least one of phase separation,distillation, and fractionation.

Aspect 45 is a method of separating trifluoroacetyl chloride (CF₃COCl)and trifluoroiodomethane (CF₃I) from a primary composition comprisingtrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I),comprising the steps of conveying a feed stream comprising the primarycomposition to a low-pressure column; collecting a first bottoms productfrom the low-pressure column, the first bottoms product consistingessentially of trifluoroacetyl chloride (CF₃COCl); conveying a firstdistillate from the low-pressure column to a high-pressure column, thefirst distillate comprising, consisting essentially of, or consisting ofan azeotrope or azeotrope-like composition consisting essentially ofeffective amounts of trifluoroacetyl chloride (CF₃COCl) andtrifluoroiodomethane (CF₃I); and collecting a second bottoms productfrom the high-pressure column, the second bottoms product consistingessentially of trifluoroiodomethane (CF₃I).

Aspect 46 is the method of Aspect 45, further comprising, after thesecond collecting step, the additional step of recycling a seconddistillate from the high-pressure column back to the feed streamcomprising the primary composition.

Aspect 47 is a method of separating trifluoroacetyl chloride (CF₃COCl)and trifluoroiodomethane (CF₃I) from a primary composition comprisingtrifluoroacetyl chloride (CF₃COCl) and trifluoroiodomethane (CF₃I),comprising the steps of conveying a feed stream comprising the primarycomposition to a high-pressure column; collecting a first bottomsproduct from the high-pressure column, the first bottoms productconsisting essentially of trifluoroiodomethane (CF₃I); conveying a firstdistillate from the high-pressure column to a low-pressure column, thefirst distillate comprising, consisting essentially of, or consisting ofan azeotrope or azeotrope-like composition consisting essentially ofeffective amounts of trifluoroacetyl chloride (CF₃COCl) andtrifluoroiodomethane (CF₃I); and collecting a second bottoms productfrom the low-pressure column, the second bottoms product consistingessentially of trifluoroacetyl chloride (CF₃COCl)

Aspect 48 is the method of Aspect 47, further comprising, after thesecond collecting step, the additional step of recycling a seconddistillate from the low-pressure column back to the feed streamcomprising the primary composition.

Aspect 49 is a method of breaking the azeotrope or azeotrope-likecomposition of any of Aspects 1-26 comprising: contacting the azeotropeor azeotrope-like composition with a solvent; extracting one of thetrifluoroiodomethane (CF₃I) and the trifluoroacetyl chloride (CF₃COCl)into the solvent to form a first composition including the solvent andone of the trifluoroiodomethane (CF₃I) and the trifluoroacetyl chloride(CF₃COCl) and a second composition comprising the other of thetrifluoroiodomethane (CF₃I) and the trifluoroacetyl chloride (CF₃COCl);and separating the first and second compositions.

Aspect 50 is the method of Aspect 49, wherein the azeotrope orazeotrope-like composition consist essentially of from about 0.5 wt. %to about 99.0 wt. % trifluoroacetyl chloride (CF₃COCl) and from about1.0 wt. % to about 99.5 wt. % trifluoroiodomethane (CF₃I).

Aspect 51 is the method of either Aspect 49 or Aspect 50, wherein thesolvent is selected from the group consisting of toluene, mineral oil,and acetonitrile.

Aspect 52 is the method of Aspect 51, wherein the solvent is toluene.

Aspect 53 is the method of any of Aspects 49-52, wherein the firstcomposition comprises trifluoroiodomethane (CF₃I) and the solvent, andthe second composition comprises trifluoroacetyl chloride (CF₃COCl).

Aspect 54 is the method of any of Aspects 49-53, wherein the separatingstep further comprises extractive distillation.

Aspect 55 is the method of any of Aspects 49-54, further comprising theadditional step, following the separating step, of distilling the firstcomposition.

Aspect 56 is the method of any of Aspects 49-55, wherein thedistillation of the first composition produces a product streamcomprising trifluoroiodomethane (CF₃I).

Aspect 57 is the method of any of Aspects 49-55, wherein thetrifluoroiodomethane (CF₃I) contains trifluoroacetyl chloride (CF₃COCl)in an amount of about 1 wt. % or less.

Aspect 58 is the method of Aspect 49, wherein the first compositioncomprises trifluoroacetyl chloride (CF₃COCl) and the solvent, and thesecond composition comprises trifluoroiodomethane (CF₃I).

Aspect 59 is the method of either Aspect 49 or Aspect 58, whereinseparating step further comprises extractive distillation.

Aspect 60 is the method of any of Aspects 49, 58, or 59, furthercomprising the additional step, following the separating step, ofdistilling the first composition.

Aspect 61 is the method of any of Aspects 49 or 58-60, wherein thedistillation of the first composition produces a product streamcomprising trifluoroacetyl chloride (CF₃COCl).

Aspect 62 is the method of any of Aspects 49 or 58-61, wherein thetrifluoroacetyl chloride (CF₃COCl) contains trifluoroiodomethane (CF₃I)in an amount of about 1 wt. % or less.

Aspect 63 method of separating the components the azeotrope orazeotrope-like composition of any of Aspects 1-26 comprising:contacting, within an extractive distillation column, the azeotrope orazeotrope-like composition with a solvent to form a first compositionincluding the solvent and one of the trifluoroiodomethane (CF₃I) and thetrifluoroacetyl chloride (CF₃COCl) and a second composition comprisingthe other of the trifluoroiodomethane (CF₃I) and the trifluoroacetylchloride (CF₃COCl); and distilling the first and second compositions toprovide a first distillate comprising trifluoroacetyl chloride (CF₃COCl)and a first bottoms product comprising the solvent andtrifluoroiodomethane (CF₃I).

Aspect 64 is the method of Aspect 63, wherein the solvent is selectedfrom the group consisting of toluene, mineral oil, and acetonitrile.

Aspect 65 is the method of Aspect 64, wherein the solvent is toluene.

Aspect 66 is the method of any of Aspects 63-65, wherein the extractivedistillation column is a single-stage flash column.

Aspect 67 is the method of any of Aspects 63-65, wherein the extractivedistillation column is a multi-stage column.

Aspect 68 is the method of any of Aspects 63-67, further comprising,after the distilling step, the additional step of purifying the firstbottoms product by distillation to produce a second distillate and asecond bottoms product.

Aspect 69 is the method of any of Aspects 63-68, wherein the seconddistillate comprises a product stream comprising trifluoroiodomethane(CF₃I).

Aspect 70 is the method of any of Aspects 63-69, wherein thetrifluoroiodomethane (CF₃I) contains trifluoroacetyl chloride (CF₃COCl)in an amount of about 1 wt. % or less.

As used herein, the phrase “within any range defined between any two ofthe foregoing values” literally means that any range may be selectedfrom any two of the values listed prior to such phrase regardless ofwhether the values are in the lower part of the listing or in the higherpart of the listing. For example, a pair of values may be selected fromtwo lower values, two higher values, or a lower value and a highervalue.

As used herein, the singular forms “a”, “an” and “the” include pluralunless the context clearly dictates otherwise. Moreover, when an amount,concentration, or other value or parameter is given as either a range,preferred range, or a list of upper preferable values and lowerpreferable values, this is to be understood as specifically disclosingall ranges formed from any pair of any upper range limit or preferredvalue and any lower range limit or preferred value, regardless ofwhether ranges are separately disclosed. Where a range of numericalvalues is recited herein, unless otherwise stated, the range is intendedto include the endpoints thereof, and all integers and fractions withinthe range. It is not intended that the scope of the disclosure belimited to the specific values recited when defining a range.

It should be understood that the foregoing description is onlyillustrative of the present disclosure. Various alternatives andmodifications can be devised by those skilled in the art withoutdeparting from the disclosure. Accordingly, the present disclosure isintended to embrace all such alternatives, modifications and variancesthat fall within the scope of the appended claims.

What is claimed is:
 1. A method of breaking an azeotrope orazeotrope-like composition comprising trifluoroiodomethane (CF₃I) andtrifluoroacetyl chloride (CF₃COCl), comprising: contacting the azeotropeor azeotrope-like composition with a solvent; extracting one of thetrifluoroiodomethane (CF₃I) and the trifluoroacetyl chloride (CF₃COCl)into the solvent to form a first composition including the solvent andone of the trifluoroiodomethane (CF₃I) and the trifluoroacetyl chloride(CF₃COCl) and a second composition comprising the other of thetrifluoroiodomethane (CF₃I) and the trifluoroacetyl chloride (CF₃COCl);and separating the first and second compositions.
 2. The method of claim1, wherein the azeotrope or azeotrope-like composition consistessentially of from about 0.5 wt. % to about 99.0 wt. % trifluoroacetylchloride (CF₃COCl) and from about 1.0 wt. % to about 99.5 wt. %trifluoroiodomethane (CF₃I).
 3. The method of claim 1, wherein thesolvent is selected from the group consisting of toluene, mineral oil,and acetonitrile.
 4. The method of claim 3, wherein the solvent istoluene.
 5. The method of claim 1, wherein the first compositioncomprises trifluoroiodomethane (CF₃I) and the solvent, and the secondcomposition comprises trifluoroacetyl chloride (CF₃COCl).
 6. The methodof claim 5, wherein the separating step further comprises extractivedistillation.
 7. The method of claim 6, further comprising theadditional step, following the separating step, of distilling the firstcomposition.
 8. The method of claim 7, wherein the distillation of thefirst composition produces a product stream comprisingtrifluoroiodomethane (CF₃I).
 9. The method of claim 8, wherein thetrifluoroiodomethane (CF₃I) contains trifluoroacetyl chloride (CF₃COCl)in an amount of about 1 wt. % or less.
 10. The method of claim 1,wherein the first composition comprises trifluoroacetyl chloride(CF₃COCl) and the solvent, and the second composition comprisestrifluoroiodomethane (CF₃I).
 11. The method of claim 10, whereinseparating step further comprises extractive distillation.
 12. Themethod of claim 10, further comprising the additional step, followingthe separating step, of distilling the first composition.
 13. The methodof claim 12, wherein distillation of the first composition produces aproduct stream comprising trifluoroacetyl chloride (CF₃COCl).
 14. Themethod of claim 13, wherein the trifluoroacetyl chloride (CF₃COCl)contains trifluoroiodomethane (CF₃I) in an amount of about 1 wt. % orless.
 15. A method of separating the components of an azeotrope orazeotrope-like composition comprising trifluoroacetyl chloride (CF₃COCl)and trifluoroiodomethane (CF₃I) comprising: contacting, within anextractive distillation column, the azeotrope or azeotrope-likecomposition with a solvent to form a first composition including thesolvent and one of the trifluoroiodomethane (CF₃I) and thetrifluoroacetyl chloride (CF₃COCl) and a second composition comprisingthe other of the trifluoroiodomethane (CF₃I) and the trifluoroacetylchloride (CF₃COCl); and distilling the first and second compositions toprovide a first distillate comprising trifluoroacetyl chloride (CF₃COCl)and a first bottoms product comprising the solvent andtrifluoroiodomethane (CF₃I).
 16. The method of claim 15, wherein thesolvent is selected from the group consisting of toluene, mineral oil,and acetonitrile.
 17. The method of claim 16, wherein the solvent istoluene.
 18. The method of claim 15, further comprising, after thedistilling step, the additional step of distilling the first bottomsproduct to produce a second distillate and a second bottoms product. 19.The method of claim 18, wherein the second distillate comprises aproduct stream comprising trifluoroiodomethane (CF₃I).
 20. The method ofclaim 19, wherein the trifluoroiodomethane (CF₃I) containstrifluoroacetyl chloride (CF₃COCl) in an amount of about 1 wt. % orless.